So I bought this Antennacraft ST2 "Scantenna"

[jonwienke]

Question, did that vertical arm that the ST2 is mounted on, that is in turn mounted to the conduit, come with your ST2?

The HORIZONTAL arm is part of the antenna. There is no vertical arm in the photo.

 

[joeuser]

What works better to mount the ST2 on. A PCV PIPE or a metal pipe.

Metal I would think...

 

[joeuser]

Yes, the vertical bracket comes with the ST2 antenna. Most the them come with a 50' coil of RG6 cable, too. And, as for using it for tv signals, I found mine didn't work very well for that. But then, I had it vertical-mounted as its made to do, and I'm between 25-30miles from the tv transmitters in Birmingham.

Thanks. I'm wondering about reinforcement of this antenna with the fiberglass bike flags, if anyone has done this or similar - did you do it during the install or after? Trying to decide if I need to build it then run reinforcement or do it while I put it together...

 

[stingray327]

Thanks. I'm wondering about reinforcement of this antenna with the fiberglass bike flags, if anyone has done this or similar - did you do it during the install or after? Trying to decide if I need to build it then run reinforcement or do it while I put it together...

I did both of my antennas using that reinforcement method before installing the antennas on the roof. Now that my antenna which is higher one has fallen apart I will put up another one and probably reinforce it. I think it will pro long the life of antenna at least in this windy area. One problem though I don't know where you can find those fiberglass bike flags now? Before I got them at Walmart.
I have heard but don't know if it is true that the newer antennas are better built for the wind.

 

[biomedbob]

I've seen fiberglass sections at Lowes that you use to assemble chimmey sweeps to a length you require. They are much more sturdy than the Bike flag things.

 

[joeuser]

OK thank you both. I'm going to support it, better safe than sorry, right?

 

[jonwienke]

Lowes has fiberglass driveway markers that are about 1/4" diameter and 5' long, would be a good alternative to the bike flag poles.

 

[stingray327]

Lowes has fiberglass driveway markers that are about 1/4" diameter and 5' long, would be a good alternative to the bike flag poles.

Which section/dept. is that located in?

 

[jonwienke]

http://www.lowes.com/pd_222125-3767...L=?Ns=p_product_qty_sales_dollar|1&facetInfo=

http://www.lowes.com/pd_222128-3767...ct_qty_sales_dollar|1&facetInfo=#BVRRWidgetID

 

[KJ6HCB]

Each leg of the tripod is screwed into the roof. Short screws obviously haha

 

[joeuser]

Just an update, I found bicycle flag & poles for 9.99 each. I went to Home Depot (no Lowes or Menards , which I prefer) and found drive way reflectors on 48" fiberglass rods at 2$ each. I got 6 & paid nearly the price for one bicycle flag pole. Just cut the reflectors off & I'm good to go. Weather permitting...

For fun I went to Radio Shark... They only have screw on connectors it seems. They wanted 5$ for one BNC male screw on. I can get 10 crimp on for ~7$ on Amazon! Just crazy!

 

[bartold]

Would this be a good antenna for p25 trunked with a frequency in the high 700's?

 

[popnokick]

If 700 mHz is all you listen to and you don't need the broad frequency coverage of the ST-2, then a dedicated antenna for the 700 mHz range is likely to do a better job. Optimum, pricey solution will be a 700 mHz omni gain antenna or Yagi beam. But before going that route you may want to try a simpler, cost effective approach: Use a TV antenna turned so it is vertically polarized. Remember, the recently relocated TV channels were moved off of 700 mHz to make way for the P25 and other public service stuff you are trying to receive. So those TV antennas are tuned for 700 mHz. You just need to change them from horizontal to vertical polarization, usually by rotating them 90 degrees on the axis when mounting. And even the "HD blade" style wall/window mount TV antennas can do wonders for the much lower price of a TV antenna than a (comparatively) expensive 700 mHz commercial comms antenna.

 

[bartold]

If 700 mHz is all you listen to and you don't need the broad frequency coverage of the ST-2, then a dedicated antenna for the 700 mHz range is likely to do a better job. Optimum, pricey solution will be a 700 mHz omni gain antenna or Yagi beam. But before going that route you may want to try a simpler, cost effective approach: Use a TV antenna turned so it is vertically polarized. Remember, the recently relocated TV channels were moved off of 700 mHz to make way for the P25 and other public service stuff you are trying to receive. So those TV antennas are tuned for 700 mHz. You just need to change them from horizontal to vertical polarization, usually by rotating them 90 degrees on the axis when mounting. And even the "HD blade" style wall/window mount TV antennas can do wonders for the much lower price of a TV antenna than a (comparatively) expensive 700 mHz commercial comms antenna.

I have a Yagi. Just not getting the reception I would like. I found out today that I have it oriented wrong. It is horizontal instead of vertical. Would that make that much of a difference? I know I have it pointed in the correct direction.

 

[popnokick]

Incorrect polarization can make a 3dB or more difference in the received signal.... for weaker signals that could be enough to bury them in the noise. For most all VHF/UHF 2-way communication you want to ensure your Yagi is vertically polarized.... that is, the elements will be vertical (perpendicular) to the ground.... not parallel to the ground like a TV antenna. Once you turn the Yagi to vertical, come back and let us all know here how much of a difference it made.

 

[joeuser]

Along these lines, I was wondering... If I want to get maximum signal from 800 towers to my north & south... I would orient my yagi east & west - so that the broadside of the antenna faces north & south, correct?

 

[Voyager]

Just cut the reflectors off & I'm good to go.

Awwww... why? Maybe they will add to the funky design...

 

[popnokick]

Along these lines, I was wondering... If I want to get maximum signal from 800 towers to my north & south... I would orient my yagi east & west - so that the broadside of the antenna faces north & south, correct?

Not at all. Doing what you describe would produce MINIMUM signals from the north and south direction. Yagi / "beam" / log periodic antennas all have a SINGLE primary direction from which they receive (or transmit). That one direction is the direction of greatest RF gain in the antenna's pattern. That is why they are called "unidirectional" as opposed to omnidirectional antennas. They receive (transmit) best from primarily one general direction. However, every Yagi / beam also has some gain in the opposite (180 degrees) direction from the primary direction. The difference in gain between those 180 degree opposites is known as the "front to back ratio". So while a beam / Yagi is not omnidirectional, if the other direction from which you want to receive is 180 degrees opposite from your weakest signals.... you may be able to "point" your beam at the weakest signal direction and take advantage of the "back lobe" to receive the stronger signals. E.g. signals from south are strongest but you also want to hear weaker signals to the north. So point the main / highest gain lobe to the north and test to see if the signals from the south are strong enough to be received by the "back of the beam". And you've just saved the cost of a rotator (which is the way beams are normally used... just like old-fashioned TV antenna beams with rotors).
And there is a possible reason to turn the beam AWAY from what you are trying to receive: if you need to null out a strong simulcast tower, turning the beam could attenuate the unwanted tower signal enough to help with receiving the desired transmission from another tower.

 

[joeuser]

@ Voyager - good idea, might keep planes from landing on my roof also!

@popnokick This gives me a lot to think about. Thank you for the info.

 

[bartold]

Incorrect polarization can make a 3dB or more difference in the received signal.... for weaker signals that could be enough to bury them in the noise. For most all VHF/UHF 2-way communication you want to ensure your Yagi is vertically polarized.... that is, the elements will be vertical (perpendicular) to the ground.... not parallel to the ground like a TV antenna. Once you turn the Yagi to vertical, come back and let us all know here how much of a difference it made.

Climbed up there today and it seems to have made a big difference. The scanner is receiving a lot better. Thanks. Now I got to figure out what setting the ATT should be on. I have a psr800. It was so much easier before we went digital.